1. Field of the Invention
Device and method for the gripping and retention of part of a split carcass by the spinal column.
2. Description of the Prior Art
The present invention relates to a device and a method for the gripping and retention of part of a split carcass by the spinal column and for conveying that part mainly in the lengthwise direction of the spinal column, while retaining it by the spinal column.
After the slaughtering of pigs for instance, the carcass is split and each half is cut into head, fore-end, middle and ham. The middle is separated into loin and belly.
The fore-end, middle and loin contain the split spinal column, which may be removed by a subsequent boning process. A mechanical process for the removal of the spinal column (and the neck bone) from fore-ends is described in Danish patent no. 172.745 B1 (Slagteriemes Forskningsinstitut). In this process, one side of the spinal column is pressed against a guide rail while another side of the spinal column is pushed in the direction of a spiked endless chain conveying the fore-end past tools which cut free the spinal column and cut through the connection to the ribs. Danish patent no. 173.009 B1 (Slagteriernes Forskningsinstitut) describes a further development of that process in which the riblet is cut free mechanically, while the fore-end is conveyed by the spiked chain.
EP 0 714 607 A1 (Stork-Protecon-Langen) describes a machine for sawing off the spinal column (the rib-top) of a middle by means of a tubular saw. The middle is conveyed by means of a belt whose spikes penetrate the spinal column.
The object of the present invention is to provide a device which is able to grip and retain part of a split carcass by the spinal column and convey that part, while retaining it by the spinal column, with a considerably better hold between the spinal column and the machine sections conveying the part, than that provided by the known processes and machines mentioned above.
The object of the invention is realised in a device which is characterised in that the device comprises a mainly rectilinear conveyor with retention elements, which are connected as links in an endless chain, that each element has a first section with a contact surface for a first side of the spinal column, and a second section with a pressure surface for a second side of the spinal column, and that the two sections of each element are designed to allow contact surface and pressure surface to be relatively moved towards and away from each other in a direction across the conveyor""s direction of conveyance.
One of the advantages of the device according to the invention, is that the contact and pressure surfaces of the retention elements can be moved relatively towards each other while the elements are being conveyed by the conveyor, allowing the spinal column to be gradually gripped and clamped between the surfaces. As the operation may be carried out successively, element by element, only relatively small forces are necessary to move the surfaces of each retention element and the sections of an element can be actuated so that a spinal column part is not finally clamped until the spinal column part in front of it has been so. (In the same way, two corresponding sections of a zip can only be coupled when the parts behind have been coupled.) The contact and pressure surfaces of the retention elements can be relatively moved towards each other to previously determined position(s) in which the spinal column is clamped, or one or both sections of the retention elements can be actuated by a force so that the movement stops when the surfaces have built up sufficient pressure on the spinal column to clamp it.
The relative movement of the contact surface and the pressure surface towards and away from each other can be provided by absolute movement of the first section, the second section or both the first and second section of a retention element.
Advantageous embodiments of the device according to the invention are:
Contact surface for the first side of the spinal column may be located on the side of a projection of retention element.
Pressure surface for the second side of the spinal column may be located on surface of a spike.
Contact surface and pressure surface can be relatively moved towards and away from each other, independently of the movement of the corresponding surfaces of neighbouring retention elements.
The device may comprise a mainly rectilinear conveyor with retention elements, which are connected as links in an endless chain, and each retention element may have a first section with two contact surfaces slanting towards each other in an acute angle, for two sides of the spinal column, and a second section designed to allow pressure surface to be moved across the conveyor""s direction of conveyance and towards and away from one of the contact surfaces, by which the spinal column can be clamped, and subsequently released from the grip.
Each retention element may comprise a console on which at least one profiled section is fastened, with a contact surface for a first side of the spinal column, and a second contact surface, slanting towards the first surface in an acute angle for a second side of the spinal column.
The two sections may be connected to each other as a hinge, and the pivot axle of the hinge may running essentially in the conveyor""s direction of conveyance.
One section may be a fixed section of retention element, whereas the other section may pivot on an axle, running essentially in the conveyor""s direction of conveyance.
Each retention element may comprise a console, which is connected to two neighbouring consoles by chain links, the retention elements may be guided by means of a rail, and the retention elements may be driven around continuously using a drive unit actuating chain links or consoles.
The device may comprise a structure running in the lengthwise direction of conveyor which structure, by actuating the first or the second or both sections of retention elements, is designed to cause a relative movement of the contact surface and pressure surface towards or away from each other.
One of the sections of the retention elements may be designed with a sensor which, when actuated by a structure towards one side or the other, moves contact or pressure surface sideways in relation to the conveyor""s direction of conveyance.
The method according to the invention is characterised in that the spinal column of part of a split carcass is successively moved to rest against retention elements connected as links in an endless chain of a mainly rectilinear conveyor, the retention elements and the spinal column being moved at an oblique angle towards each other, from a position with a spinal column part near a first section of an element with a contact surface for one side of the spinal column and a second section of the same element with a pressure surface for a second side of the spinal column, to a position where the spinal column part is in contact with contact surface and/or pressure surface of the retention element, that the contact and pressure surfaces of the retention elements are successively moved relatively towards each other in a direction across the conveyor""s direction of conveyance, causing a substantial part of the spinal column to be eventually gripped and retained between the contact and pressure surfaces of the elements, and that the part of a split carcass is moved in the conveyor""s direction of the conveyance while being retained by the elements.
Advantageous embodiments of the method according to the invention are:
Retention elements, whose pressure surface is located on surface of a spike may be used, and the contact and pressure surfaces may be moved so close towards each other that the spike penetrates the spinal column.
Contact and pressure surfaces may be moved relatively towards and away from each other, independently of the movement of the corresponding surfaces of neighbouring retention elements.
Contact and pressure surfaces may be moved relatively towards each other by swivelling around a common pivot axle, which runs parallel to the conveyor""s direction of conveyance.
In the present description a (carcass) part means especially the fore-end, loin and middle of a pig carcass. However, the invention may also be applied to other (carcass) parts, especially those of cattle, sheep, goats and similar carcasses.
During retention of part of a split carcass by the spinal column the carcass part may be processed by means of cutting tools, e.g. saws and knives separating meat and bone in for-ends or middles.